The present invention relates to solid state relays, and in particular, to a solid state relay which utilizes TRIAC driven TRIACs in conjunction with SCR driven SCRs.
For many years, relay circuits have provided the ability to manipulate large currents and voltages in a main circuit by making minute changes in the parameters of a low power circuit. In this manner, for example, a low voltage (or current) automobile ignition key switch can control the delivery of a significantly larger amount of power from the car battery to the starter. Traditionally, this was accomplished inductively with relays that were bulky and rather expensive. In recent years, however, advances in the field of solid state technology have provided an assortment of lighter, smaller, and less expensive relays.
Although most solid state relays utilize a TRIAC as the main switch of the relay and use a DIAC to drive the TRIAC into its ON or OFF state, it is in many cases more desirable to utilize a TRIAC driven TRIAC or an SCR driven SCR to perform the ON and OFF function of the relay. In still further cases, it would be even more desirable for the user to selectively choose the type of relay circuit used (TRIAC or SCR) according to his/her particular needs, especially if these needs change.